drivers/acpi/namespace/nsnames.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsnames - Name manipulation and search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2005, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44
  45 #include <acpi/acpi.h>
  46 #include <acpi/amlcode.h>
  47 #include <acpi/acnamesp.h>
  48
  49
  50 #define _COMPONENT          ACPI_NAMESPACE
  51          ACPI_MODULE_NAME    ("nsnames")
  52
  53 /* Local prototypes */
  54
  55 static void
  56 acpi_ns_build_external_path (
  57         struct acpi_namespace_node      *node,
  58         acpi_size                       size,
  59         char                            *name_buffer);
  60
  61
  62 /*******************************************************************************
  63  *
  64  * FUNCTION:    acpi_ns_build_external_path
  65  *
  66  * PARAMETERS:  Node            - NS node whose pathname is needed
  67  *              Size            - Size of the pathname
  68  *              *name_buffer    - Where to return the pathname
  69  *
  70  * RETURN:      Places the pathname into the name_buffer, in external format
  71  *              (name segments separated by path separators)
  72  *
  73  * DESCRIPTION: Generate a full pathaname
  74  *
  75  ******************************************************************************/
  76
  77 static void
  78 acpi_ns_build_external_path (
  79         struct acpi_namespace_node      *node,
  80         acpi_size                       size,
  81         char                            *name_buffer)
  82 {
  83         acpi_size                       index;
  84         struct acpi_namespace_node      *parent_node;
  85
  86
  87         ACPI_FUNCTION_NAME ("ns_build_external_path");
  88
  89
  90         /* Special case for root */
  91
  92         index = size - 1;
  93         if (index < ACPI_NAME_SIZE) {
  94                 name_buffer[0] = AML_ROOT_PREFIX;
  95                 name_buffer[1] = 0;
  96                 return;
  97         }
  98
  99         /* Store terminator byte, then build name backwards */
 100
 101         parent_node = node;
 102         name_buffer[index] = 0;
 103
 104         while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
 105                 index -= ACPI_NAME_SIZE;
 106
 107                 /* Put the name into the buffer */
 108
 109                 ACPI_MOVE_32_TO_32 ((name_buffer + index), &parent_node->name);
 110                 parent_node = acpi_ns_get_parent_node (parent_node);
 111
 112                 /* Prefix name with the path separator */
 113
 114                 index--;
 115                 name_buffer[index] = ACPI_PATH_SEPARATOR;
 116         }
 117
 118         /* Overwrite final separator with the root prefix character */
 119
 120         name_buffer[index] = AML_ROOT_PREFIX;
 121
 122         if (index != 0) {
 123                 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
 124                         "Could not construct pathname; index=%X, size=%X, Path=%s\n",
 125                         (u32) index, (u32) size, &name_buffer[size]));
 126         }
 127
 128         return;
 129 }
 130
 131
 132 #ifdef ACPI_DEBUG_OUTPUT
 133 /*******************************************************************************
 134  *
 135  * FUNCTION:    acpi_ns_get_external_pathname
 136  *
 137  * PARAMETERS:  Node            - Namespace node whose pathname is needed
 138  *
 139  * RETURN:      Pointer to storage containing the fully qualified name of
 140  *              the node, In external format (name segments separated by path
 141  *              separators.)
 142  *
 143  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
 144  *
 145  ******************************************************************************/
 146
 147 char *
 148 acpi_ns_get_external_pathname (
 149         struct acpi_namespace_node      *node)
 150 {
 151         char                            *name_buffer;
 152         acpi_size                       size;
 153
 154
 155         ACPI_FUNCTION_TRACE_PTR ("ns_get_external_pathname", node);
 156
 157
 158         /* Calculate required buffer size based on depth below root */
 159
 160         size = acpi_ns_get_pathname_length (node);
 161
 162         /* Allocate a buffer to be returned to caller */
 163
 164         name_buffer = ACPI_MEM_CALLOCATE (size);
 165         if (!name_buffer) {
 166                 ACPI_REPORT_ERROR (("ns_get_table_pathname: allocation failure\n"));
 167                 return_PTR (NULL);
 168         }
 169
 170         /* Build the path in the allocated buffer */
 171
 172         acpi_ns_build_external_path (node, size, name_buffer);
 173         return_PTR (name_buffer);
 174 }
 175 #endif
 176
 177
 178 /*******************************************************************************
 179  *
 180  * FUNCTION:    acpi_ns_get_pathname_length
 181  *
 182  * PARAMETERS:  Node        - Namespace node
 183  *
 184  * RETURN:      Length of path, including prefix
 185  *
 186  * DESCRIPTION: Get the length of the pathname string for this node
 187  *
 188  ******************************************************************************/
 189
 190 acpi_size
 191 acpi_ns_get_pathname_length (
 192         struct acpi_namespace_node      *node)
 193 {
 194         acpi_size                       size;
 195         struct acpi_namespace_node      *next_node;
 196
 197
 198         ACPI_FUNCTION_ENTRY ();
 199
 200
 201         /*
 202          * Compute length of pathname as 5 * number of name segments.
 203          * Go back up the parent tree to the root
 204          */
 205         size = 0;
 206         next_node = node;
 207
 208         while (next_node && (next_node != acpi_gbl_root_node)) {
 209                 size += ACPI_PATH_SEGMENT_LENGTH;
 210                 next_node = acpi_ns_get_parent_node (next_node);
 211         }
 212
 213         if (!size) {
 214                 size = 1;       /* Root node case */
 215         }
 216
 217         return (size + 1);  /* +1 for null string terminator */
 218 }
 219
 220
 221 /*******************************************************************************
 222  *
 223  * FUNCTION:    acpi_ns_handle_to_pathname
 224  *
 225  * PARAMETERS:  target_handle           - Handle of named object whose name is
 226  *                                        to be found
 227  *              Buffer                  - Where the pathname is returned
 228  *
 229  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
 230  *
 231  * DESCRIPTION: Build and return a full namespace pathname
 232  *
 233  ******************************************************************************/
 234
 235 acpi_status
 236 acpi_ns_handle_to_pathname (
 237         acpi_handle                     target_handle,
 238         struct acpi_buffer              *buffer)
 239 {
 240         acpi_status                     status;
 241         struct acpi_namespace_node      *node;
 242         acpi_size                       required_size;
 243
 244
 245         ACPI_FUNCTION_TRACE_PTR ("ns_handle_to_pathname", target_handle);
 246
 247
 248         node = acpi_ns_map_handle_to_node (target_handle);
 249         if (!node) {
 250                 return_ACPI_STATUS (AE_BAD_PARAMETER);
 251         }
 252
 253         /* Determine size required for the caller buffer */
 254
 255         required_size = acpi_ns_get_pathname_length (node);
 256
 257         /* Validate/Allocate/Clear caller buffer */
 258
 259         status = acpi_ut_initialize_buffer (buffer, required_size);
 260         if (ACPI_FAILURE (status)) {
 261                 return_ACPI_STATUS (status);
 262         }
 263
 264         /* Build the path in the caller buffer */
 265
 266         acpi_ns_build_external_path (node, required_size, buffer->pointer);
 267
 268         ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "%s [%X] \n",
 269                 (char *) buffer->pointer, (u32) required_size));
 270         return_ACPI_STATUS (AE_OK);
 271 }
 272
 273